Physical vapor deposition (PVD) is commonly utilized for forming thin layers of material on substrates, for example semiconductor substrates. A sputtering target, usually including a backing plate, is provided proximate to a substrate within an appropriate chamber and forming an upper portion of a PVD sputter chamber. The backing plate often rests on a ceramic insulating ring. In some processes, the temperature of the target and the chamber increases during processing thermal expansion of the target backing plate and the chamber wall. The thermal expansion of the target backing plate and the chamber wall may be different, and have been observed by the inventors to cause the target backing plate and the insulating ring to move relative to each other, causing friction. The friction has been observed to cause the backing plate and the insulating ring to grind together, causing portions of the backing plate to wear at the interface. The worn material may contaminate the chamber.
Accordingly, the inventors have provided a target assembly that may advantageously reduce the friction at an interface between the target and the PVD chamber.